Lesson hydrochloric acid and its salts. Open lesson in chemistry on the topic "Hydrochloric acid and its salts" (Grade 9)

Lesson development (lesson notes)

UMK line O. S. Gabrielyan. Chemistry (8-9)

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WMC"Chemistry. Grade 9 "O. S. Gabrielyan.

Lesson type: combined.

Goals:

a) cognitive to form the ability to characterize the properties of sulfuric acid in the light of theory electrolytic dissociation, redox reactions, confirm with the corresponding equations chemical reactions;

b) developing - complication semantic function speech, the ability to analyze, generalize, compare;

c) educating - tolerant attitude to the statements of others, discipline and composure.

Tasks:

specify general knowledge students about the properties of acids in the light of the theory of electrolytic dissociation (TED) using the example of dilute sulfuric acid;
refine students' knowledge of oxidizing properties acids on the example of concentrated sulfuric acid;
show the national economic significance of this acid and its salts.

Equipment and materials: sulfuric acid (diluted and concentrated), for concentrated acid you need a pipette or glass tube, zinc granules, copper wire, sodium hydroxide solution, sodium carbonate solution, barium chloride solution, powdered sugar, splinter, white cardboard sheet, test tubes, desiccator, filter paper, burner, dry fuel, matches; computer, projector, screen, computer presentation; on the student desks spread out periodic system chemical elements DI. Mendeleev and "Table of solubility of acids, bases and salts in water", as well as the scheme "Interaction of concentrated sulfuric acid with metals".

Used sources:

Handbook of the teacher. Chemistry. Grade 9 Gabrielyan O.S., Ostroumov I.G.,
Chemistry. Grade 9 Textbook. Gabrielyan O.S.

During the classes

Preliminary preparation: assignments written on the blackboard by the teacher:

1) Carry out a chain of transformations:

2) Calculate the volume of air required to burn 320 mg of sulfur.

3) Write molecular equations chemical reactions that characterize the properties of hydrochloric acid.

I. Organizational moment

greetings;
preparing students for the lesson;
mark absent in the class journal;
obligatory placement of bags on hooks on the desks (to free the passage between the rows).

II. Homework check step

(The teacher calls one student to the board at recess, checks homework and asks the student to write correct solution On the desk.)

Teacher: Guys, the homework was set. On the blackboard, they wrote the correct solution to the homework, check with your performance and notes. Raise your hand, please, those whose solution and notes match those written on the board. And now those who have inaccuracies? If you haven't done your homework, please raise your hand. At recess, approach the teacher and explain the reason. (The teacher must record the names of those who did not complete their homework and find out the reasons during the break, making appropriate entries in the diaries.)

III. The stage of preparing students for learning new material

1. Interviewing students at the blackboard

Teacher: Guys, we already have a lot of information about the properties of sulfur-containing substances, how to obtain them. Let's remember the main points together, and for this we will complete the tasks written on the board. (The teacher first reads out the tasks written on the board, and then calls three students at will.)

1.1. One student completes the task "Perform a chain of transformations:

1.2. The second student solves the problem "Calculate the volume of air that is needed to burn 320 mg of sulfur"

1.3. The third student completes the task "Write the molecular equations of chemical reactions that characterize the properties of hydrochloric acid"

2. Actualization of knowledge in the form of a conversation

(While the students are doing the tasks on the board, the teacher is having a conversation with the students.)

Class Interview: (Teacher advises that students may take notes in their workbooks if necessary.)

– Indicate the location of the chemical element sulfur in the Periodic Table of Chemical Elements;

- Calculate the number elementary particles in a sulfur atom (the number of protons, electrons and neutrons);

- Write and read electronic formula a sulfur atom;

- Indicate what oxidation states sulfur can exhibit in complex substances;

- Give examples of sulfur compounds, where it exhibits oxidation states 0, -2, +2, +4, +6;

– Make formulas for sulfur oxides and indicate the nature of these sulfur oxides;

– Make formulas of the corresponding hydroxides and indicate the nature of these hydroxides;

– List with which classes inorganic compounds sulfurous and sulfuric acids will react.

3. Checking completed tasks by students at the blackboard

The teacher asks to comment on the completed assignments, makes comments if necessary, aloud calls the assessment of each student with a small comment.

4. Theme, goals and objectives

The teacher, with the help of students, formulates the purpose of the lesson: "To study the chemical properties of sulfuric acid of different concentrations."

IV. The stage of assimilation of new material

1. Properties of dilute sulfuric acid

Teacher using slide #2 computer presentation, introduces students to the physical properties of concentrated acid and demonstrates it in a bottle and in a test tube, for comparison, demonstrates a solution of sulfuric acid.

These are typical properties of acids, which are also characteristic of dilute sulfuric acid. The teacher asks the children to write down the reaction equations for H 2 SO 4 (deciphered) in molecular form:

with metals up to (H 2), for example with Zn, (slide No. 5)
with metal oxides (basic and amphoteric), for example, with MgO and ZnO (slide No. 6);
with bases, for example with NaOH, depending on the ratio of the amount of sulfuric acid and base, different salts can be formed (slide No. 7.8)
with salts, for example with Ca 3 (PO 4) 2 (slide No. 9)

(At the moment when the students write off the equations from the board, the teacher conducts a demonstration chemical experiments confirming typical Chemical properties dilute sulfuric acid.)

Students, in order to save time, watch the demonstration of experiments conducted by the teacher.

2. Physical education

The teacher gives the students a small physical education minute.

3. Properties of concentrated sulfuric acid (slide No. 10).

The teacher demonstrates the following experiments:

dilution of concentrated sulfuric acid (it is necessary to repeat the corresponding rule: “acid is poured into water”);
hygroscopic properties of H 2 SO 4 (concentrated) (slide No. 11):
charring of a splinter, paper, powdered sugar (demonstration of experience);
use in a desiccator for drying substances;
the interaction of concentrated sulfuric acid (slide #12) with metals, the teacher explains, is completely different from the reaction of dilute acid with them.

Obviously, due to the fact that it contains very little water (for example, concentrated laboratory acid is only 2%), the oxidizing agents will not be H + cations (they are not in such a “solution” of the acid), but the sulfuric acid molecules themselves (more precisely, S +6 included in it). Therefore, H 2 SO 4 (concentrated) oxidizes many metals, regardless of their position in the voltage series, while forming not H 2, but recovering to S, SO 2 or H 2 S, depending on the metal and reaction conditions.

The interaction of H 2 SO 4 (concentrated) with copper when heated is demonstrated and analyzed from the point of view of OVR (for this, the teacher calls one student to the blackboard, who arranges the coefficients in this reaction equation using the electronic balance method):

Cu 0 + 2H 2 S + 6O 4 \u003d Cu + 2SO 4 + S + 4O 2 + 2H 2 O

The teacher should emphasize that H 2 SO 4 (concentrated) does not react with some metals when normal conditions(standard), for example, with iron, aluminum, chrome, gold. Therefore, it can be stored in iron containers, transported in steel tanks.

Teacher: In order to determine in which case which substance S, SO 2 or H 2 S to write, you need to use the hint in the form of a diagram, which is on your table in the form handout, as well as on slide No. 13, please write it down in your workbook.

Teacher: Guys, please write at home the equations of chemical reactions of the interaction of concentrated sulfuric acid with sodium and silver, arrange the coefficients using the electronic balance method

4. Salts of sulfuric acid

As a dibasic acid, H 2 SO 4 dissociates in solution in steps:

H 2 SO 4 \u003d H + + HSO 4 - (1 stage)

HSO 4 - \u003d H + + SO 4 2 - (stage 2)

Sulfuric acid forms two series of salts:

acidic, or hydrosulfates, for example, NaHSO 4,
medium (normal), or sulfates, for example, Na 2 SO 4.

All hydrosulfates and most sulfates are highly soluble in water.

5. Qualitative reaction to sulfate ion (slide No. 14)

The teacher asks students to define the concept qualitative reaction”, name the reagents for the chloride ion and, using the “Table of the solubility of acids, bases and salts in water”, determine which ions can be used to conduct a qualitative reaction to the sulfate ion. Then he gives explanations why it is the barium ion, and not others proposed by the students, who conducts a demonstration experiment.

Therefore, the reagent for the sulfate ion is the barium ion:

Ba +2 + SO 4 2– = BaSO 4

(If time permits, you can talk about the representatives of salts, recall crystalline hydrates, show samples of natural materials, gypsum, etc.)

Teacher: Guys, at home, please, using the reduced ionic equation, restore the full ionic and molecular equations.

6. Application of sulfuric acid

The teacher, using slide No. 15, briefly introduces students to the areas of application of sulfuric acid, its significance in national economy and production.

V. Stage of consolidation of new knowledge

- List the classes of inorganic substances that dilute sulfuric acid can react with.

What condition must be met for the reaction of sulfuric acid and base to form an acid salt?

Name the ions into which normal and acid salts sulfuric acid.

Name the reaction products formed when dilute sulfuric acid reacts with metals.

- Name the reaction products that can be formed when concentrated sulfuric acid reacts with metals.

- Determine and name what substances will be formed when concentrated sulfuric acid reacts with:

calcium
mercury
iron (no reaction)
barium
aluminum
silver.

- Name the metals with which concentrated sulfuric acid will not react under standard conditions.

– Name the ion that is used to determine the presence of sulfate ion in the proposed solution.

VI. The stage of informing students about homework

Teacher: Guys, at the end of our lesson, look again at the screen, where in this moment there is a homework slide and check if the whole assignment has been recorded in your workbooks. If there concrete questions on assignments, then ask. Pay your attention to the fact that the task is from the textbook. (slide number 16)

(At the very end of the lesson, the teacher reminds that students who have not completed their homework for this lesson should come up at recess)

VII. The stage of summing up the lesson

The teacher sums up the lesson, calls the marks of the students who answered at the blackboard; marks the most active and the most passive students; thanks for the lesson.

Republic of Crimea

Belogorsky district

Municipal treasury educational institution

"Litvinenkovskaya secondary school"

Chemistry lesson in grade 9

Subject: Hydrochloric acid and her salt

Lesson focused on textbook Rudzitis G.E., Feldman F.G. Chemistry. Grade 9 Moscow, Prosveshchenie, 2014

Teacher Ryzhenkova V.V.

Litvinenkovo 2016

Lesson goals.

Learning goal : to summarize knowledge about the properties of acids using the example of hydrochloric acid, to study the specific properties of hydrochloric acid and its salts; consider obtaining hydrochloric acid in the laboratory and in industry, the importance of hydrochloric acid and its salts.

Development goal : develop the ability to analyze information, establish cause-and-effect relationships between phenomena; develop skills in solving computational problems in chemistry, compiling equations of chemical reactions in molecular, ionic form, skills in experimental work.

educational goal : to cultivate a culture of health; responsibility for the subject.

Equipment : computer, laptops, projector, laboratory tripod, demonstration test tubes, Mendeleev's Periodic Table of Chemical Elements, Activity series of metals, table of solubility of acids, salts and bases.

Reagents : water, hydrochloric acid, solutions of sodium chloride, sodium sulfate, nitric acid, silver nitrate, litmus solution.

Basic concepts and terms : bond length, bond polarity, electrolytes, dissociation, acids, salts, oxidizing agent, reducing agent, qualitative reaction.

Lesson type : lesson learning new material.

Teaching methods : verbal, visual, partially - search, interactive (" Brainstorm”, “Work in groups”), the method of motivation for learning, the method of test control.

Lesson structure

I.Organizational stage - 2 min

II.Updating basic knowledge - 5 min

III.Learning new material -25 min

1. Study of the physical properties of hydrochloric acid (first group)

2. Obtaining hydrochloric acid in the laboratory and in industry (second group)

3. Chemical properties of hydrochloric acid common to all acids (third group)

4. Specific properties of hydrochloric acid and its salts (fourth group)

5. The meaning and use of hydrochloric acid and its salts (fifth group)

IV.Consolidation of knowledge and skills - 10 min

V.Homework- 2 minutes

VI.Summing up the lesson - 1 min

During the classes

I .Organizational stage

Greetings. Diagnosis of the emotional state of students. Interactive technology "Smiley". On the fields workbook draw a smiley reflecting your emotional condition. In the case when the majority of students have poor emotional health, you should talk with the guys, trying to change their mood and set them up for work.

The message of the topic and purpose of the lesson (slide 1).

The teacher's explanation of how to work with the cards "Rating of the student in the lesson"for self-assessment of knowledge (Appendix No. 1)

II .Updating basic knowledge

Heuristic conversation

1. How does the radius of the atom change for the elements of group VII-A within the group from top to bottom?

2. Name the formulas of volatile hydrogen compounds elements of group VII-A.

3. What are aqueous solutions volatile hydrogen compounds of elements of group VII-A? (acids)

4. Are these acids electrolytes and why?

5. How does the strength of hydrohalic acids as electrolytes change in a series

HF→ HCl→ HBr→ HI? (Amplified acid properties as the bond length increases). slide 2

6.What safety precautions should we know when working with acids? (Safety briefing: hydrochloric acid can cause chemical burns if handled carelessly)

Motivation

The teacher says that the program provides for the study of the properties of hydrochloric acid.

staging problematic issue: "Why, of all the hydrohalic acids, do we study hydrochloric acid?"

Suggested student responses:

Less hazardous substance;

More accessible;

It has greater value for a person.

Connection with biology. Recall biological role hydrochloric acid (biology grade 8). Hydrochloric acid is part of the gastric juice, activates the enzyme pepsin, which breaks down proteins. Lack of acid leads to indigestion. Excess acid (high acidity) causes heartburn, corrodes the walls of the esophagus and stomach.

Teacher talks about the dangers of self-treatment, for example, the use of "pop" (soda solution) for heartburn. Experience: Interaction of soda and almagel with acid.

In medicine, a 0.3-0.5% solution of hydrochloric acid with the enzyme pepsin is prescribed for patients with insufficient acidity.

III . Learning new material

Learning activities organized by interactive technology collectively - group learning"Work in pairs".

The teacher invites the children to independently unite in five research groups. The task of the groups is to acquire knowledge at the level necessary to share this information with others. Completion time is seven minutes. Each group reports its part of the information within 3-4 minutes.

Tasks for work in groups

I Group : Determine which of the two test tubes given to you contains hydrochloric acid, and which contains water. Describe physical properties dilute and concentrated hydrochloric acid with the help of their observations and textbook data, p.56.
II Group : read the textbook article (p. 56, fig. 13) and study the methods for obtaining hydrochloric acid in the laboratory and in industry. Write Equations relevant reactions. What volume of hydrogen is required to produce 10 liters of hydrogen chloride.

III Group : Explore the chemical properties of acids using hydrochloric acid as an example. Perform exercise 2 on page 58 of the textbook. Draw a diagram showing the chemical properties of hydrochloric acid in common with other acids.

IV Group : Learn the specific properties of hydrochloric acid and its salts

a) the interaction of hydrochloric acid and its salts with silver nitrate (I)-qualitative reaction to chloride - ions. Study the textbook material page 57, table 9 "Specific properties of hydrochloric acid" and section! Important information page 57. Spend laboratory experience"Recognition of hydrochloric acid and its salts", make equations for the corresponding chemical reactions and describe the signs of reactions. Make a conclusion based on your observations. Use the Experiment Guide. (Appendix No. 2) or page 60 of the textbook.

b) interaction with oxidizing agents. Study the textbook material on page 57 table 9. Make an equation for oxidative - reducing reaction using the electronic balance method, using the algorithm given in paragraph 1 on page 6.K 2 Cr 2 O 7 + HCl → Cl 2 + CrCl 3 +…+…

V Group : Learn the uses of hydrochloric acid and its salts. Prepare your presentation. Slides 3-4.

Suggested responses from students.

IGroup : We recognize hydrochloric acid with a universal indicator paper. In a test tube with acid, it is pink, which means that there are hydrogen cations in a solution of hydrochloric acid - H + which is true for all acids.

Teacher : Hydrochloric acid - strong electrolyte. The degree of its dissociation in dilute solutions reaches 90%. Dissociation equation HCl → H + +Сl - (chloride - ion). Salts - chlorides.

Pupils: Hydrochloric acid is a colorless, volatile liquid. Technical acid is yellow due to impurities of chlorine or iron. At a temperature of 20 0 With it is possible to obtain hydrochloric acid with a mass fraction of hydrogen chloride of 37-38%. At 0 0 With 507 volumes of HCl dissolve in 1 volume of water, this corresponds to a concentration of 45%. In moist air, concentrated hydrochloric acid "smoke" strongly, because. it releases hydrogen chloride. There is a strong smell.

II Group : In the laboratory, hydrochloric acid is obtained by reacting table salt with concentrated sulfuric acid (2: 1)

NaCl(crystal)+H 2 SO 4 (conc.)=NaHSO 4 + HClat a temperature of 150 0 With

excess hydrosulfate

sodium

Obtaining hydrochloric acid in this way was developed by alchemists.

With an excess of salt and a temperature of 550 0 WITH:

2NaCl+H 2 SO 4 =Na 2 SO 4 +2HCl

Explanation according to figure 13 page 56 or bookmark on the Internet (video experiments). Slides 8-9.

Production in industry: combustion of hydrogen in chlorine and dissolution of the reaction product in water.

H 2 + Cl 2 =2 HCl

1l H 2 ____ 2lHCl X \u003d 5l (H 2 )

ChlN 2 -10lHCl

III Group :

Which of the following substances will react with hydrochloric acid? Make up the equations of the corresponding reactions, write one of them in ionic form.

HCl

Zn Cu Al CaO SiO2 Fe2 O3 NaOHAl(OH)3 Fe 2 (SO 4 ) 3 CaCO3 Fe(NO3 ) 3

1.Zn+HCl= ZnCl 2 +H 2

2.Al+6HCl=2AlCl 3 + 3H 2

3. CaO+2HCl=CaCl 2 +H 2 O

4. Fe 2 O 3 +6 HCl=2FeCl 3 +3H 2 O

5. NaOH + HCl=NaCl+H 2 O

6 Al(OH) 3 +3HCl=AlCl 3 +3H 2 O

7. CaCO 3 +2HCl=CaCl 2 +CO 2 +H 2 O

Students summarize the material in the form of a diagram or table (slide 5).Conclusion: hydrochloric acid exhibits chemical properties typical of the class of acids.

IV Group

a) Pupils talk about the results of the experiment, write down the equations of chemical reactions. Interaction with silver nitrate (silver nitrate is a reagent for hydrochloric acid and its salts); in three test tubes, the formation of a white cheesy precipitate was observed, which does not dissolve in either water or acids:

HCl+AgNO 3 =AgCl↓+HNO 3

NaCl+AgNO 3 = AgCl↓+NaNO 3

CaCl 2 +2 AgNO 3 =2 AgCl↓+Ca(NO 3 ) 2

The conclusion is formulated: the interaction of hydrochloric acid and its salts with silver (I) nitrate is a qualitative reaction for chloride ions:

Ag + + Cl - = AgCl ↓

Teacher: to recognize other halides (bromides, iodides), you can also use silver cations (Appendix 2 "Definition of ions", pp. 202-203 of the textbook).

Video experience "Recognition of halides" (found on a bookmark on the Internet).

b) interaction with oxidizing agents

K 2 Cr 2 O 7 +14 HCl=3 Cl 2 +2 CrCl 3 +2 KCl+7 H 2 O

Cr +6 +3 e→ Cr +3 2 reduction, oxidizer

2 Cl - 2 e→ Cl 2 0 3 oxidation, reducing agent

V Group : Hydrochloric acid is used to obtain chlorides, hydrogen; in the leather industry for leather processing; in medicine; during the hydrolysis of wood; for pickling steel, i.e. cleaning its surface from corrosion products before coating with a layer of protective metal (nickel plating, chromium plating), otherwise the metal will not stick to the steel surface. AT Food Industry hydrochloric acid is used as food supplement E-507 as an acidity regulator.

Presentation "Application of chlorides"

IV. Consolidation of knowledge and skills of students

Task : What volume of chlorine will be released when 29.4 g of potassium dichromate react with an excess of hydrochloric acid.

Mr (K 2 Cr 2 O 7 ) = 294 a.u.m

. M(K 2 Cr 2 O 7 ) = 294g/mol

29.4g x

K 2 Cr 2 O 7 +14 HCl=3 Cl 2 +2 CrCl 3 +2 KCl+7 H 2 O

294g 3mol

X= 0.3 mol V=0.3 mol . 22.4 l / mol \u003d 67.2 l

Answer: 67.2 liters of chlorine

Testing.

1. Substances with which hydrochloric acid does not react are

BUT chromiumAT carbon monoxide(IV)

B sodium sulfateG iron(III) hydroxide

2. The reagent for determining chloride ions in solution is

BUT barium nitrateAT barium chloride

B silver nitrateG silver chloride

3. Hydrochloric acid is

BUT strong electrolyteB weak electrolyte

4. A pair of ions that can simultaneously be in solution is

BUT H + andSiO 3 2- AT H + andSO 4 2-

B Xi 2+ and he - G Ag + and Cl -

Code:1-B, 2-B, 3-A, 4-B

V. Homework: Study Practice #3 in paragraph 11, pp.59-60

VI. Students sum up their work, fill out rating cards and report points to the teacher. The teacher converts points into grades. Thank you for your work in class. You can check the emotional state of the guys (smiley).

Application No. 1

5. Search work (abstracts, presentations, etc.)

6.Testing

Outcome

50/score5

Application №2

Instructions for conducting a laboratory experiment "Recognition of hydrochloric acid and its salts"

Remember! Hydrochloric acid is corrosive!

Pour 1-2 ml of dilute hydrochloric acid into one test tube, the same amount of sodium chloride solution into the second, and calcium chloride solution into the third. Add a few drops of silver(I) nitrate solution to each tube. Check if the precipitate is soluble in concentrated nitric acid.

Write the equations of the reactions carried out and answer the question, what is the reagent for hydrochloric acid and its salts.

Chemistry lesson in grade 9

Topic: "Hydrochloric acid and its salts".

Target:study the chemical properties of hydrochloric acid, and consider the applications of this acid.

Tasks:

educational - in the process of research, study the chemical properties of hydrochloric acid and get acquainted with the qualitative reaction to the chloride ion.

Educational- to develop further skills to make equations of chemical reactions; learn to compare, generalize, analyze and draw conclusions.

Educational- develop cognitive activity through experiment.

Equipment and reagents: periodic system of chemical elements, solubility table, rack with test tubes, hydrochloric acid, sodium hydroxide, silver nitrate, blue litmus, methyl orange, phenolphthalein.

Activation techniques mental activity students:

1. Analysis of educational information.

2. Disclosure intersubject communications between chemistry, physics, biology.

3. Putting forward hypotheses.

4. Analysis and drawing up generalizing conclusions.

Lesson structure.

1. organizational stage.

2. Updating of basic knowledge.

3. Learning new material.

1. Staging learning task. Goal setting.

2. “Discovery” of new knowledge by children.

3. Studying the methods of obtaining and properties of hydrochloric acid ..

4. Physical education.

5. Laboratory experiment No. 2

4. Generalization and systematization of knowledge.

5. Homework.

6. Summing up the lesson. Reflection.

During the classes.

1. organizational stage.

2. Updating of basic knowledge.

Greeting students, creating emotional mood and motivation to learn new material. In the last lesson, we met with gaseous substance- hydrogen chloride.

1. What is the formula of hydrogen chloride?

2. How is hydrogen chloride produced? Write the equations of chemical reactions.

3. What are the properties and uses of hydrogen chloride?

4. What is formed if hydrogen chloride is dissolved in water?

3. Learning new material.

Teacher. Indeed, when hydrogen chloride is dissolved in water, hydrochloric acid is formed.And thereforeThe topic of our lesson is “Hydrochloric acid and its properties”. Let's define the goals of our lesson together. The motto of our lesson will be the words of Goethe:"Just knowing is not everything, knowledge must be used."

You will have to show how you can use your knowledge in different situations. First, let's remember what we know about acids. So the first question is:

1) What is an acid?

2) From the biology course, remember where hydrochloric acid is found in the human body?

3) What do acids taste like?

4) How do you work with acids?

Teacher. Let's start our acquaintance with hydrochloric acid by studying how to obtain it.

Getting hydrochloric acid:

1. In industry, it is obtained by burning hydrogen in chlorine and dissolving the reaction product in water.

2. In the laboratory H2SO4 + 2NaCl → 2HCl + Na2SO4

Physical properties:

concentrated hydrochloric acid ( mass fraction hydrogen chloride is 37%) - it is a colorless solution, strongly fuming in humid air, with a pungent odor due to the release of hydrogen chloride. (slide 3 video of the experiment "Properties of fuming hydrochloric acid")

This gas is easily soluble in water: up to 450 volumes of hydrogen chloride - in one volume of water. In a test tube, hydrochloric acid is formed - a solution of hydrogen chloride in water.

Chemical properties:

1) Changing the color of the indicator (litmus - red)

2) Interacts with metals (if the metal is in the series compiled by N.N. Beketov to hydrogen, then hydrogen is released and a salt is formed.

Exclusion of HNO3 (other gases are released)

Mg + 2HCl → MgCl2 + H2

2 Al + 6 HCl → 2 AlCl 3 + 3 H 2

Cu + HCl →

3) Interacts with the main and amphoteric oxides:

MgO + 2HCl → MgCl2 + H2O

ZnO + 2 HCl → ZnCl2 + H2O

4) Interacts with bases:

HCl + KOH → KCl + H2O

3 HCl + Al (OH) 3 → AlCl 3 + 3 H 2 O

5) It interacts with salts (in accordance with a number of acids, each previous acid can displace the next one from the salt), another acid and another salt are formed.

CaCO3 + 2HCl → CaCl2 + H2O + CO2

6) Interacts with oxidizing agents (MnO2, KMO4, KClO3)

6HCl + KClO3 = KCl + 3H2O + 3Cl2

7) Interacts with silver nitrate, precipitates white color which is insoluble in water or acids.

HCl + AgNO3 → AgCl↓ + HNO3

Silver nitrate is a reagent for hydrochloric acid and its salts i.e. used as a qualitative reaction to recognize chloride ions.

Laboratory experience No. 2.(students perform a laboratory experiment, getting acquainted with a qualitative reaction to chloride ions)

Subject. Qualitative reactions to hydrochloric acid and its salts.

Working process.

Safety briefing.

In test tubes with a solution of hydrochloric acid and sodium chloride, add a few drops of a solution of silver nitrate AgNO3 (qualitative reaction for chloride ion Cl-). What are you watching? Write reaction equations in molecular and ionic form.

Reaction equations: HCl + AgNO3 =

NaCl + AgNO3 =

At the end of the work, students write down the conclusion.

The use of hydrochloric acid and its salts:

Hydrochloric acid is part of the gastric juice and promotes the digestion of protein foods in humans and animals.

Hydrogen chloride and hydrochloric acid are used to produce drugs, dyes, solvents, and plastics.

The use of basic salts of hydrochloric acid:

KCl - fertilizer, also used in glass and chemical industry.

HgCl2 - sublimate - poison, used for disinfection in medicine, for dressing seeds in agriculture.

NaCl- salt- raw materials for the production of hydrochloric acid, sodium hydroxide, hydrogen, chlorine, bleach, soda. It is used in the leather and soap industries, in cooking and canning.

ZnCl2 - for wood impregnation against decay, in medicine, when soldering.

AgCl - used in black and white photography, as it has photosensitivity - decomposes in the light to form free silver: 2AgCl => 2Ag + Cl2

4. Generalization and systematization of knowledge.

Tasks for repetition and consolidation

No. 1. Carry out the transformations according to the scheme:

HF → F2 → FeF3 → Fe(OH)3 → Fe2O3 → FeF3 → F2

No. 2. Substances given:

Ca, Au, Fe(II), ZnO, FeO, LiOH, Fe(OH)3, FeSO4, Na2CO3, Fe(NO3)2

Which of the following substances will react with hydrochloric acid.

5. Homework. §15, ex. No. 2,3, TK p.58.

6. Summing up the lesson. Reflection.

Teacher : Today in the lesson we deepened our knowledge of acids, getting acquainted in more detail with hydrochloric acid. And now I would like you to evaluate the level of your knowledge after this lesson. Put a "+" next to the statements that you think are true for yourself.

1) After the lesson, I began (a) to know more.

2) Deepened (a) knowledge on the topic, I can apply them in practice.

3) At the lesson there was something to think about.

4) I received (a) answers to all questions that arose during the lesson.

5) At the lesson, I worked in good faith and achieved the objectives of the lesson (la).

Teacher: At the end of the work, please raise the hands of those who put

5 "+"; 4 "+"; 3

Lesson in grade 8 on the topic: Hydrochloric acid and its salts.

Purpose: to study the chemical properties of hydrochloric acid, and consider the scope of this acid.
Tasks:
Educational - in the process of research, study the chemical properties of hydrochloric acid and get acquainted with the qualitative reaction to the chloride ion.
Developing - to develop further skills in composing equations of chemical reactions; learn to compare, generalize, analyze and draw conclusions.
Educational - to develop cognitive activity through experiment.

Type of lesson: a lesson in the assimilation of new knowledge.

Teaching method: explanatory-illustrative, problem-search, practical work, the use of ICT.
Organizational forms: conversation, practical work, student messages.

Equipment and reagents: periodic system of chemical elements, solubility table, rack with test tubes, hydrochloric acid, sodium hydroxide, silver nitrate, copper, magnesium, aluminum, blue litmus, methyl orange, phenolphthalein.
Techniques for activating the mental activity of students:
Analysis of educational information.
Disclosure of interdisciplinary connections between chemistry, physics, biology.
Putting forward hypotheses.
Analysis and drawing up generalizing conclusions.
During the classes.

introduction teachers:
The topic of our lesson is “Hydrochloric acid and its properties”.
The motto of our lesson will be the words of Goethe:
"Just knowing is not everything, knowledge must be used."
You will have to show how you can use your knowledge in different situations. First, let's remember what we know about acids. So the first question is:
What is an acid? (a complex substance consisting of hydrogen atoms and an acid residue).
How many hydrogen atoms can there be in acids? How are they classified on this basis? (one-, two-, three-base). Give examples.
What can replace hydrogen? What does this result in? (metals; salts).
Define salt. ( Complex Substances, consisting of metal atoms and an acid residue).
Physical properties:
Concentrated hydrochloric acid (mass fraction of hydrogen chloride is 37%) is a colorless solution, strongly fuming in humid air, with a pungent odor due to the release of hydrogen chloride.
Getting hydrochloric acid:
1. In industry, it is obtained by burning hydrogen in chlorine and dissolving the reaction product in water.
2. In the laboratory H2SO4 + 2NaCl 2HCl + Na2SO4
This gas is easily soluble in water: up to 450 volumes of hydrogen chloride - in one volume of water. In a test tube, hydrochloric acid is formed - a solution of hydrogen chloride in water.
Chemical properties:
1) Changing the color of the indicator (litmus-red)
2) Interacts with metals (if the metal is in the series compiled by N.N. Beketov to hydrogen, then hydrogen is released and a salt is formed.
Exclusion of HNO3 (other gases are released)

Mg + 2HCl MgCl2 + H2 2Al + 6HCl 2AlCl3 + 3H2 Cu + HCl

Practical work
3) Interacts with basic and amphoteric oxides:

MgO + 2HCl MgCl2 + H2O ZnO + 2HCl ZnCl2 + H2O

4) Interacts with bases:

HCl + KOH KCl + H2O 3HCl + Al(OH)3 AlCl3 + 3H2O

5) It interacts with salts (in accordance with a number of acids, each previous acid can displace the next one from the salt), another acid and another salt are formed.
HNO3
H2SO4, HCl, H2SO3, H2CO3, H2S, H2SiO3

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H3PO4

CaCO3 + 2HCl CaCl2 + H2O + CO2

6) It interacts with silver nitrate, a white precipitate forms, which is not soluble in either water or acids.

HCl + AgNO3 AgCl + HNO3

Silver nitrate is a reagent for hydrochloric acid and its salts i.e. used as a qualitative reaction to recognize chloride ions.
Practical work

7) Interacts with oxidizing agents (MnO2, KMO4, KClO3)

6HCl + KClO3 = KCl + 3H2O + 3Cl2
Conclusion: in all the reactions we studied, chlorides were obtained - salts of hydrochloric acid.

We turn to the study of salts of hydrochloric acid, which are called chlorides.
Salts of hydrochloric acid are chlorides.
Receipt:
1. Interaction of metals with chlorine.
2Fe + 3Cl2 2FeCl3
2. Interaction of hydrochloric acid with metals.
Mg + 2HCl MgCl2 + H2
3. Interaction of hydrochloric acid with oxides
CaO + 2HCl CaCl2 + H2O
4. Interaction of hydrochloric acid with hydroxides
Ba(OH)2 + 2HCl BaCl2 + 2H2O
5. Interaction of hydrochloric acid with some salts
Pb(NO3)2 + 2HCl PbCl2 + 2HNO3

Most chlorides are soluble in water (with the exception of silver, lead and monovalent mercury chlorides).

The use of hydrochloric acid and its salts:

Hydrochloric acid is part of the gastric juice and promotes the digestion of protein foods in humans and animals.
Hydrogen chloride and hydrochloric acid are used to produce drugs, dyes, solvents, and plastics.
The use of basic salts of hydrochloric acid:
KCl is a fertilizer, also used in the glass and chemical industries.
HgCl2 - sublimate - poison, used for disinfection in medicine, for dressing seeds in agriculture.
NaCl - table salt - raw material for the production of hydrochloric acid, sodium hydroxide, hydrogen, chlorine, bleach, soda. It is used in the leather and soap industries, in cooking and canning.
ZnCl2 - for wood impregnation against decay, in medicine, when soldering.
AgCl - used in black and white photography, as it has photosensitivity - decomposes in the light to form free silver: 2AgCl => 2Ag + Cl2

Tasks for repetition and consolidation

No. 1. Carry out the transformations according to the scheme:
HCl Cl2 AlCl3 Al(OH)3 Al2O3 AlCl3 Cl2
No. 2. Substances given:
Zn, Cu, Al, MgO, SiO2, Fe2O3, NaOH, Al(OH)3, Fe2(SO4)3, CaCO3, Fe(NO3)3
Which of the following substances will react with hydrochloric acid. Write the equations of chemical reactions
No. 3. Solve the problem:
How much aluminum will react with an excess of hydrochloric acid to produce 5.6 liters of hydrogen (N.O.)?

D / Z p. 49, task 4-5 p. 169.

Reflection
The teacher (together with the students evaluates the lesson, accepts their suggestions and wishes).
Guys, what did each of you learn in today's lesson?
Have you mastered the concepts: "chlorides", "inhibitor", "qualitative reaction"?
What did you like or dislike about the lesson and why?
Students answer questions, evaluate the completeness of the knowledge gained, and self-evaluate their work. Identify the most interesting and complete answers, justify their point of view.
The degree of fulfillment of educational goals is revealed.

Depending on the degree of dilution with water, that is, on the concentration, the physical properties of nitric acid will be different.

Anhydrous fresh Nitric acid- a colorless, water-like liquid with a pungent odor, miscible with water in any ratio. When stored under the influence of light or temperature, nitric acid partially decomposes with the release of nitric oxide (IV) - a brown gas:

4HNO 3 \u003d 4NO 2 + O 2 + 2H 2 O

Due to the released oxygen, a smoldering splinter over heated nitric acid flares up. Brown gas dissolves in acid and colors it in yellow. Substances containing protein, when concentrated nitric acid comes into contact with them, turn yellow. Therefore, nitric acid leaves yellow spots on the skin of the hands. To avoid this, you should work with concentrated nitric acid in rubber gloves.

Nitric acid is a strong inorganic acid. Therefore, it is characterized by all general properties acids: discoloration of indicators, interaction with basic and amphoteric oxides, bases and salts. But nitric acid is still a very strong oxidizing agent, therefore it reacts with metals in a special way.

The nature of the interaction of nitric acid with metals is rather complicated. These redox reactions do not belong to the type of substitution, and the composition of the products of such reactions is very diverse. Moreover, nitric acid, even diluted, is able to interact with metals that are in the activity series to the right of hydrogen.

Only gold, platinum, osmium, iridium and tantalum do not interact with nitric acid under any circumstances.

Some active metals, such as aluminum, do not react with nitric acid due to the dense oxide film that forms on the surface of the metal. In order to show the activity of aluminum, we lower the aluminum wire into a solution of hydrochloric acid. Aluminum reacts vigorously with hydrochloric acid to release hydrogen.

2Al + 6HCl = 3H 2 + 2AlCl 3

Then we lower the same wire into concentrated nitric acid. Immediately, a very thin oxide film is formed on the aluminum surface, which prevents the interaction of the metal with the acid.

In most reactions of concentrated nitric acid with metals, the reduction product of nitric acid will be nitric oxide (IV). For example, when iron reacts with concentrated nitric acid, when heated, iron (III) nitrate, nitric oxide (IV) and water are formed:

Fe + 6HNO 3 (conc.) = Fe(NO 3) 3 + 3NO 2 + 3H 2 O

The coefficients in such reactions are placed using the electronic balance method.

Let's do an experiment. Let's observe how dilute and concentrated nitric acid reacts with metals. Prepare two test tubes with a solution of nitric acid. Let's put zinc in the first, copper in the second.

Zinc reacts with highly dilute nitric acid to release ammonia.

4Zn + 9HNO 3 \u003d NH 3 + 4Zn (NO 3) 2 + 3H 2 O

Wet litmus paper turns blue at the neck of the test tube, indicating the presence of ammonia. Copper reacts with a solution of nitric acid to release nitrogen monoxide.

3Cu + 8HNO 3 = NO + 3Cu(NO 3) 2 + 4H 2 O

Concentrated nitric acid is an even stronger oxidizing agent. Place zinc and copper in test tubes with concentrated nitric acid. Zinc and copper react violently with concentrated nitric acid to form soluble salts and release brown gas - nitrogen dioxide (Fig. 1).

Zn + 4HNO 3 \u003d 2NO 2 + 2H 2 O + Zn (NO 3) 2

Cu + 4HNO 3 \u003d 2NO 2 + 2H 2 O + Cu (NO 3) 2

Rice. 1. Interaction of copper (left) and zinc (right) with concentrated nitric acid

When interacting with most metals, concentrated nitric acid is reduced to nitrogen dioxide.

Salts of nitric acid are called nitrates. In addition, salts of nitric acid alkali metals, calcium and ammonium ion are called nitrates. For example, NH 4 NO 3 is ammonium nitrate.

All nitrates are highly soluble in water and thermally unstable. All of them decompose when heated with the release of oxygen. Moreover, depending on the cation, the decomposition products may vary.

At thermal decomposition potassium nitrate, potassium nitrite and oxygen are predominantly formed:

2KNO 3 \u003d 2KNO 2 + O 2

During the thermolysis of copper (II) nitrate, copper (II) oxide, nitrogen dioxide and oxygen are formed:

2Cu(NO 3) 2 \u003d 2CuO + 4NO 2 + O 2

Nitric acid is a large-tonnage product of the chemical industry. It is widely used for the production of dyes, explosives, nitrogen fertilizers and medicines.

In laboratory practice, nitric acid and especially its mixture with hydrochloric acid (the so-called aqua regia) are used to dissolve metals that are insoluble in other acids.

Bibliography

Orzhekovsky P.A. Collection of tasks and exercises in chemistry: 9th grade: to the textbook by P.A. Orzhekovsky and others. “Chemistry. Grade 9 / P.A. Orzhekovsky, N.A. Titov, F.F. Hegel. - M.: AST: Astrel, 2007.
Orzhekovsky P.A. Chemistry: 9th grade: textbook. for general inst. / P.A. Orzhekovsky, L.M. Meshcheryakova, L.S. Pontak. - M.: AST: Astrel, 2007. (§ 37)
Orzhekovsky P.A. Chemistry: 9th grade: textbook for general education. inst. / P.A. Orzhekovsky, L.M. Meshcheryakova, M.M. Shalashova. - M.: Astrel, 2013. (§ 24)
Rudzitis G.E. Chemistry: inorgan. chemistry. Organ. chemistry: textbook. for 9 cells. / G.E. Rudzitis, F.G. Feldman. - M .: Education, JSC "Moscow textbooks", 2009.
Khomchenko I.D. Collection of tasks and exercises in chemistry for high school. - M.: RIA "New Wave": Publisher Umerenkov, 2008.
Encyclopedia for children. Volume 17. Chemistry / Chapter. ed. V.A. Volodin, leading. scientific ed. I. Leenson. - M.: Avanta +, 2003.

Single collection of digital educational resources(video experiences on the topic) ().
Electronic version of the journal "Chemistry and Life" ().

Homework

with. 160 Nos. 5, 7 from the textbook P.A. Orzhekovsky "Chemistry: 9th grade" / P.A. Orzhekovsky, L.M. Meshcheryakova, M.M. Shalashova. - M.: Astrel, 2013.